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Asteroid YU55 to swing close by Earth on Tuesday. Can we see it?

Asteroid YU55 is about to swing by Earth, coming closer to our planet than the moon. It will make its closest approach at exactly 6:28 p.m. Eastern on Tuesday.

The event marks the first time that something this big has come this close to Earth since 1976, and the scientists who have been tracking it on a daily basis since Friday are giddy with anticipation.

"It is just a great scientific opportunity. It is really, really exciting," Marina Brozovic, a scientist and member of the JPL Goldstone radar team, told The Times.

Brozovic will be using a powerful radar telescope to figure out the exact topography of the asteroid, and get a better read on its size and composition, but what about the rest of us? Can we get in on the asteroid action?

The answer is ... kind of, but not really.

"If you aren't already a pretty serious amateur astronomer, this is not the time or the place to start," said Alan MacRobert, senior editor of Sky and Telescope Magazine.

In an interview with The Times, MacRobert explained that despite the asteroid being fairly large (roughly a quarter- mile in diameter), and fairly close, it will still be 11th magnitude at best on Tuesday night, which means it will be 100 times dimmer than what you could see with the naked eye in a perfectly dark, wilderness sky.

In order to see YU55, you would need a 6- to 8- inch telescope, as well as experience in reading and using a detailed sky chart.

Further, the moon will be fairly bright, and the light will get in your way.

If you did know what you were doing, however, you'd find that the asteroid would look like a faint star among lots of other stars. And, as you watch it from one second to the next, you would see it gradually creeping across the sky in real time.

"Most asteroids don't do that," said MacRobert. "They stay put and you have to look away for a few minutes in order to notice any movement. But this one is close enough that you can see it move."

Image: Scientists will use giant instruments like this one from the Deep Space Network, managed by JPL for NASA, to track asteroid YU55. But will anyone else get to see it? Credit: Agence France-Presse / NASA